Method for treating noise-induced hearing loss (NIHL)

Abstract

A method for treating noise-induced hearing loss (NIHL) includes the step administering a composition to the mammal, wherein the composition consists essentially of a biologically effective amount of vitamin A, vitamin E, vitamin C, a vasodilator comprising magnesium, and, optionally, a withanolide, and / or resveratrol.

Description

RELATED APPLICATIONS[0001]This patent application is a continuation-in-part of U.S. patent application Ser. No. 14 / 847,178 filed on Sep. 8, 2015. U.S. patent application Ser. No. 14 / 847,178 is a continuation-in-part of U.S. patent application Ser. No. 13 / 839,760 filed on Mar. 15, 2013, which is now U.S. Pat. No. 9,144,565. U.S. patent application Ser. No. 13 / 839,760 is a continuation-in-part of U.S. patent application Ser. No. 13 / 679,224 filed on Nov. 16, 2012, which is now U.S. Pat. No. 8,927,528. U.S. patent application Ser. No. 13 / 679,224 is a continuation-in-part of U.S. patent application Ser. No. 12 / 761,121 filed on Apr. 15, 2010, which is now U.S. Pat. No. 8,338,397. U.S. patent application Ser. No. 12 / 761,121 is a continuation-in-part of U.S. patent application Ser. No. 11 / 623,888 filed on Jan. 17, 2007, which is now U.S. Pat. No. 7,951,845. U.S. patent application Ser. No. 11 / 623,888 claims priority to and all advantages of U.S. Provisional Patent Application No. 60 / 760,055...

AI Technical Summary

Benefits of technology

[0012]The composition of the present disclosure may be used for treating noise-induced hearing loss, and includes components that function through different biological mechanisms to provide an additive effect that is equal to or greater than a sum of the effect of the individual components. In essence, the composition includes a biologically effective amount of at least one scavenger of singlet oxygen, a donor antioxidant, a third antioxidant, and a vasodilator. The at least one scavenger of singlet oxygen may be present for reducing free radicals that contribute to hearing loss. The donor antioxidant may be present for reducing peroxyl radicals and inhibiting propagation of lipid peroxidation that also contributes to hearing loss. The vasodilator may be present for preventing decreases in both cochlear blood flow and oxygenation that also contribute to hearing loss.

[0013]The composition, when presented daily during repeated noise exposures, is significantly effective in reducing damage to the inner ear and NIHL from repeated exposure to high noise levels. As used herein, high noise levels include those at which hearing loss is induced, such as repeated exposure to noise at 85 decibels (dB) and above for about 8 hours per day. Typically, as the noise level increases above 85 dB, the time for exposure decreases. In an example, for every 6 dB increase in noise level, the exposure time decreases by about half. For instance, a person exposed to a noise level of about 115 dB (such as at a high level rock concert), hearing loss may occur at an exposure of about 15 minutes. It is to be appreciated that, in certain instances, hearing loss may be induced at noise levels less than 85 dB, such as at 80 dB or even as low as 75 dB. The noise level that induces hearing loss may depend, at least in part, on genetics and / or a person's sensitivity toward particular noises that result in hearing loss.

[0014]The method for treating noise-induced hearing loss from repeated exposure to high noise levels, described in detail below, may be used to reduce or even prevent NIHL of in mammals, particularly humans, that are repeatedly exposed to noise at levels that typically result in hearing impairment. Examples of noise levels that typically result in hearing impairment include, but are not limited to, occupational noise exposures, military noise exposures, and repeated noisy leisure time activities. As a result, the composition and method for treating noise-induced hearing loss provide great promise to minimizing hearing loss resulting from trauma to the inner ear(s) of a mammal. Given the high incidence of noise-induced hearing loss in the general population worldwide, there is a great need for the composition and method of the present disclosure to minimize socioeconomic effects that persist due, at least in part, to noise-induced hearing loss.

Problems solved by technology

NIHL is a leading cause of acquired hearing impairment in the industrialized world.

For example, more than twenty million United States workers are typically exposed to potentially hazardously high noise levels while working.

In addition, about one-third of returning military personnel have suffered disabling hearing impairments.

Noise levels high enough to cause hearing loss (i.e., intense noise) can cause hearing impairment by two mechanisms: 1) direct mechanical damage to delicate structures of the inner ear and / or 2) intense metabolic damage.

Noise-induced mechanical damage to the inner ear is caused from energy of sufficient intensity to break apart membranes of the inner ear tissue(s), such as exposure to a blast injury or explosion.

Noise-induced metabolic damage is typically caused from oxidative stress in the cells of the inner ear, the formation of free radicals, and a resulting decrease in blood flow to the inner ear.

Urban environments are increasingly noisy, and there is a rapidly increasing percentage of the world's population living in urban environments.

In addition to increasing environmental and industrial noises, high levels of noise exposure from rapid adoption of digital music technologies and personal listening devices places about 1.1 billion people worldwide at risk for early onset of noise-induced hearing loss.

Intense noise is an environmental stress factor for the ear that may cause damage to the ear, which may lead to cell death.

For instance, intense noise can cause damage to micromechanical properties of sensory transducers in the ear, changes in blood flow in the ear, modification in intracellular ion transport properties, depletion of sensory cell transmitter substances (e.g. glutamate), changes in post synaptic membrane transmitter receptors (e.g. gluR) on afferent nerve fibers, modification of dispersion and uptake properties of transmitters in extracellular, synaptic spaces, and / or changes in postsynaptic membrane biophysical properties that may affect space- and time-constant properties modifying depolarization.

Intense noise can also cause changes of an excitotoxic nature in postsynaptic membranes, causing destruction of afferent neural tissues.

Any one or more of these changes may result in modification of spontaneous activity in individual or small populations of afferent nerve fibers, which can result in a change in the sensitivity of hearing and / or the perception of tinnitus.

Additionally, intense noise (i.e., high noise levels sufficient to cause hearing loss) demands greater activity of the respiratory chain to create adenosine triphosphate (ATP), resulting in excess free radical formation.

However, under high levels of stress, increased free radical formation may contribute to excitotoxicity and can damage the DNA.

Through the process of lipid peroxidation, the increased free radical formation can destroy inner and extracellular membranes that can lead to temporary loss in hearing sensitivity, distortions of sounds, muffling of sounds, and permanent hearing loss associated with cell death.

Stress induced hearing loss becomes evermore prevalent in the ageing inner ear with reduced blood flow and reduced efficiency of antioxidant systems.

Dietary supplements including ginkgo biloba, melatonin, zinc, lipoflavenoids, and vitamin supplements are available for treating hearing loss; however, no evidence is available that any of these supplements are actually beneficial for NIHL or tinnitus.

In addition, no chemical treatments have been attempted to prevent repeated exposure to high noise levels leading to NIHL.

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